package leetcode.easy;

import leetcode.base.TreeNode;

public class $572_IsSubtree {
    public boolean isSubtree(TreeNode root, TreeNode subRoot) {
        if (root == null && subRoot == null) {
            return true;
        }
        if (root == null || subRoot == null) {
            return false;
        }
        if (isSameTree(root, subRoot)) {
            return true;
        }
        return isSubtree(root.left, subRoot) || isSubtree(root.right, subRoot);
    }


    boolean isSameTree(TreeNode p, TreeNode q) {
        if ((p == null && q != null) || (p != null && q == null)) {
            return false;
        }
        if (p == null && q == null)
            return true;
        if (p.val != q.val) {
            return false;
        } else {
            return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
        }
    }
}
